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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2008 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: LLPInputStream.html 21 2014-09-19 19:17:15Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.dellroad.hl7.llp;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import java.io.BufferedInputStream;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import java.io.EOFException;<a name="line.11"></a>
<span class="sourceLineNo">012</span>import java.io.IOException;<a name="line.12"></a>
<span class="sourceLineNo">013</span>import java.io.InputStream;<a name="line.13"></a>
<span class="sourceLineNo">014</span><a name="line.14"></a>
<span class="sourceLineNo">015</span>import org.dellroad.hl7.HL7ContentException;<a name="line.15"></a>
<span class="sourceLineNo">016</span>import org.dellroad.hl7.HL7Message;<a name="line.16"></a>
<span class="sourceLineNo">017</span>import org.dellroad.hl7.HL7Reader;<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>/**<a name="line.19"></a>
<span class="sourceLineNo">020</span> * Reads HL7 messages framed in the "lower layer protocol" (LLP).<a name="line.20"></a>
<span class="sourceLineNo">021</span> */<a name="line.21"></a>
<span class="sourceLineNo">022</span>public class LLPInputStream implements HL7Reader {<a name="line.22"></a>
<span class="sourceLineNo">023</span><a name="line.23"></a>
<span class="sourceLineNo">024</span>    private static final int MIN_BUFLEN = 1024;<a name="line.24"></a>
<span class="sourceLineNo">025</span>    private static final int MAX_BUFLEN = 16 * 1024;<a name="line.25"></a>
<span class="sourceLineNo">026</span><a name="line.26"></a>
<span class="sourceLineNo">027</span>    private final BufferedInputStream inputStream;<a name="line.27"></a>
<span class="sourceLineNo">028</span>    private final int maxLength;<a name="line.28"></a>
<span class="sourceLineNo">029</span><a name="line.29"></a>
<span class="sourceLineNo">030</span>    private byte[] buf = new byte[MIN_BUFLEN];<a name="line.30"></a>
<span class="sourceLineNo">031</span><a name="line.31"></a>
<span class="sourceLineNo">032</span>    /**<a name="line.32"></a>
<span class="sourceLineNo">033</span>     * Constructor.<a name="line.33"></a>
<span class="sourceLineNo">034</span>     *<a name="line.34"></a>
<span class="sourceLineNo">035</span>     * @param in underlying input stream<a name="line.35"></a>
<span class="sourceLineNo">036</span>     * @param maxLength maximum allowed message length<a name="line.36"></a>
<span class="sourceLineNo">037</span>     * @throws IllegalArgumentException if out is null<a name="line.37"></a>
<span class="sourceLineNo">038</span>     * @throws IllegalArgumentException if maxLength is negative<a name="line.38"></a>
<span class="sourceLineNo">039</span>     */<a name="line.39"></a>
<span class="sourceLineNo">040</span>    public LLPInputStream(InputStream in, int maxLength) {<a name="line.40"></a>
<span class="sourceLineNo">041</span>        if (in == null)<a name="line.41"></a>
<span class="sourceLineNo">042</span>            throw new IllegalArgumentException("in is null");<a name="line.42"></a>
<span class="sourceLineNo">043</span>        if (maxLength &lt; 0)<a name="line.43"></a>
<span class="sourceLineNo">044</span>            throw new IllegalArgumentException("maxLength is negative");<a name="line.44"></a>
<span class="sourceLineNo">045</span>        this.inputStream = new BufferedInputStream(in);<a name="line.45"></a>
<span class="sourceLineNo">046</span>        this.maxLength = maxLength;<a name="line.46"></a>
<span class="sourceLineNo">047</span>    }<a name="line.47"></a>
<span class="sourceLineNo">048</span><a name="line.48"></a>
<span class="sourceLineNo">049</span>    /**<a name="line.49"></a>
<span class="sourceLineNo">050</span>     * Read next message from the underlying stream.<a name="line.50"></a>
<span class="sourceLineNo">051</span>     *<a name="line.51"></a>
<span class="sourceLineNo">052</span>     * @throws EOFException if there is no more input<a name="line.52"></a>
<span class="sourceLineNo">053</span>     * @throws HL7ContentException if a malformed message is read<a name="line.53"></a>
<span class="sourceLineNo">054</span>     * @throws LLPException if illegal framing byte(s) are read from the underlying stream, or the message is too long<a name="line.54"></a>
<span class="sourceLineNo">055</span>     * @throws IOException if an error occurs on the underlying stream<a name="line.55"></a>
<span class="sourceLineNo">056</span>     */<a name="line.56"></a>
<span class="sourceLineNo">057</span>    public HL7Message readMessage() throws IOException, HL7ContentException {<a name="line.57"></a>
<span class="sourceLineNo">058</span><a name="line.58"></a>
<span class="sourceLineNo">059</span>        // Read leading byte<a name="line.59"></a>
<span class="sourceLineNo">060</span>        this.readByte(LLPConstants.LEADING_BYTE);<a name="line.60"></a>
<span class="sourceLineNo">061</span><a name="line.61"></a>
<span class="sourceLineNo">062</span>        // Read message until first trailing byte<a name="line.62"></a>
<span class="sourceLineNo">063</span>        int len = 0;<a name="line.63"></a>
<span class="sourceLineNo">064</span>        while (true) {<a name="line.64"></a>
<span class="sourceLineNo">065</span>            int ch;<a name="line.65"></a>
<span class="sourceLineNo">066</span>            if ((ch = this.inputStream.read()) == -1)<a name="line.66"></a>
<span class="sourceLineNo">067</span>                throw new EOFException();<a name="line.67"></a>
<span class="sourceLineNo">068</span>            if (ch == LLPConstants.TRAILING_BYTE_0)<a name="line.68"></a>
<span class="sourceLineNo">069</span>                break;<a name="line.69"></a>
<span class="sourceLineNo">070</span>            if (len &gt;= this.maxLength)<a name="line.70"></a>
<span class="sourceLineNo">071</span>                throw new LLPException("message is too long (greater than " + this.maxLength + " bytes)");<a name="line.71"></a>
<span class="sourceLineNo">072</span>            if (len == this.buf.length) {<a name="line.72"></a>
<span class="sourceLineNo">073</span>                byte[] newbuf = new byte[this.buf.length * 2];<a name="line.73"></a>
<span class="sourceLineNo">074</span>                System.arraycopy(this.buf, 0, newbuf, 0, len);<a name="line.74"></a>
<span class="sourceLineNo">075</span>                this.buf = newbuf;<a name="line.75"></a>
<span class="sourceLineNo">076</span>            }<a name="line.76"></a>
<span class="sourceLineNo">077</span>            this.buf[len++] = (byte)ch;<a name="line.77"></a>
<span class="sourceLineNo">078</span>        }<a name="line.78"></a>
<span class="sourceLineNo">079</span><a name="line.79"></a>
<span class="sourceLineNo">080</span>        // Read second trailing byte<a name="line.80"></a>
<span class="sourceLineNo">081</span>        this.readByte(LLPConstants.TRAILING_BYTE_1);<a name="line.81"></a>
<span class="sourceLineNo">082</span><a name="line.82"></a>
<span class="sourceLineNo">083</span>        // Extract message text<a name="line.83"></a>
<span class="sourceLineNo">084</span>        String text = new String(buf, 0, len, LLPConstants.CHARACTER_ENCODING);<a name="line.84"></a>
<span class="sourceLineNo">085</span>        if (this.buf.length &gt; MAX_BUFLEN)<a name="line.85"></a>
<span class="sourceLineNo">086</span>            this.buf = new byte[MIN_BUFLEN];<a name="line.86"></a>
<span class="sourceLineNo">087</span><a name="line.87"></a>
<span class="sourceLineNo">088</span>        // Return parsed message<a name="line.88"></a>
<span class="sourceLineNo">089</span>        try {<a name="line.89"></a>
<span class="sourceLineNo">090</span>            return new HL7Message(text);<a name="line.90"></a>
<span class="sourceLineNo">091</span>        } catch (HL7ContentException e) {<a name="line.91"></a>
<span class="sourceLineNo">092</span>            throw e.setContent(text);<a name="line.92"></a>
<span class="sourceLineNo">093</span>        }<a name="line.93"></a>
<span class="sourceLineNo">094</span>    }<a name="line.94"></a>
<span class="sourceLineNo">095</span><a name="line.95"></a>
<span class="sourceLineNo">096</span>    /**<a name="line.96"></a>
<span class="sourceLineNo">097</span>     * Advance past the end of the current message. This method can be used (for example) to skip over the remaining portion<a name="line.97"></a>
<span class="sourceLineNo">098</span>     * of a badly framed message that resulted in a {@link LLPException} in an attempt to salvage the connection.<a name="line.98"></a>
<span class="sourceLineNo">099</span>     *<a name="line.99"></a>
<span class="sourceLineNo">100</span>     * &lt;p&gt;<a name="line.100"></a>
<span class="sourceLineNo">101</span>     * This method just reads until the next occurrence of a {@link LLPConstants#TRAILING_BYTE_0} byte<a name="line.101"></a>
<span class="sourceLineNo">102</span>     * followed immediately by a {@link LLPConstants#TRAILING_BYTE_1} byte, then returns.<a name="line.102"></a>
<span class="sourceLineNo">103</span>     *<a name="line.103"></a>
<span class="sourceLineNo">104</span>     * @throws EOFException if there is no more input<a name="line.104"></a>
<span class="sourceLineNo">105</span>     * @throws IOException if an error occurs on the underlying stream<a name="line.105"></a>
<span class="sourceLineNo">106</span>     */<a name="line.106"></a>
<span class="sourceLineNo">107</span>    public void skip() throws IOException {<a name="line.107"></a>
<span class="sourceLineNo">108</span>        int state = 0;<a name="line.108"></a>
<span class="sourceLineNo">109</span>        while (true) {<a name="line.109"></a>
<span class="sourceLineNo">110</span>            int ch = this.inputStream.read();<a name="line.110"></a>
<span class="sourceLineNo">111</span>            if (ch == -1)<a name="line.111"></a>
<span class="sourceLineNo">112</span>                throw new EOFException();<a name="line.112"></a>
<span class="sourceLineNo">113</span>            if (state == 0) {<a name="line.113"></a>
<span class="sourceLineNo">114</span>                if (ch == LLPConstants.TRAILING_BYTE_0)<a name="line.114"></a>
<span class="sourceLineNo">115</span>                    state = 1;<a name="line.115"></a>
<span class="sourceLineNo">116</span>            } else {<a name="line.116"></a>
<span class="sourceLineNo">117</span>                if (ch == LLPConstants.TRAILING_BYTE_1)<a name="line.117"></a>
<span class="sourceLineNo">118</span>                    return;<a name="line.118"></a>
<span class="sourceLineNo">119</span>                state = 0;<a name="line.119"></a>
<span class="sourceLineNo">120</span>            }<a name="line.120"></a>
<span class="sourceLineNo">121</span>        }<a name="line.121"></a>
<span class="sourceLineNo">122</span>    }<a name="line.122"></a>
<span class="sourceLineNo">123</span><a name="line.123"></a>
<span class="sourceLineNo">124</span>    private void readByte(int value) throws IOException {<a name="line.124"></a>
<span class="sourceLineNo">125</span>        int ch;<a name="line.125"></a>
<span class="sourceLineNo">126</span>        if ((ch = this.inputStream.read()) == -1)<a name="line.126"></a>
<span class="sourceLineNo">127</span>            throw new EOFException();<a name="line.127"></a>
<span class="sourceLineNo">128</span>        if (ch != value) {<a name="line.128"></a>
<span class="sourceLineNo">129</span>            String expected = String.format("0x%02x", value);<a name="line.129"></a>
<span class="sourceLineNo">130</span>            String actual = String.format("0x%02x", ch);<a name="line.130"></a>
<span class="sourceLineNo">131</span>            throw new LLPException("expected to read " + expected + " but read " + actual + " instead");<a name="line.131"></a>
<span class="sourceLineNo">132</span>        }<a name="line.132"></a>
<span class="sourceLineNo">133</span>    }<a name="line.133"></a>
<span class="sourceLineNo">134</span><a name="line.134"></a>
<span class="sourceLineNo">135</span>    /**<a name="line.135"></a>
<span class="sourceLineNo">136</span>     * Close the underlying stream.<a name="line.136"></a>
<span class="sourceLineNo">137</span>     */<a name="line.137"></a>
<span class="sourceLineNo">138</span>    public void close() throws IOException {<a name="line.138"></a>
<span class="sourceLineNo">139</span>        this.inputStream.close();<a name="line.139"></a>
<span class="sourceLineNo">140</span>    }<a name="line.140"></a>
<span class="sourceLineNo">141</span>}<a name="line.141"></a>
<span class="sourceLineNo">142</span><a name="line.142"></a>




























































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